Display screen or portion thereof with transitional graphical user interface



FIG. 1 is the first image in a sequence for a display screen or portionthereof with transitional graphical user interface showing my newdesign;

FIG. 2 is the second image thereof;

FIG. 3 is the third image thereof;

FIG. 4 is the fourth image thereof;

FIG. 5 is the fifth image thereof; and,

FIG. 6 is the sixth image thereof.

The outermost broken line in the figures depicts a display screen orportion thereof that forms no part of the claimed design. The remainingbroken lines in the figures depict portions of the transitionalgraphical user interface that form no part of the claimed design.

The appearance of the transitional graphical user interface sequentiallytransitions between the images shown in FIGS. 1 through 6. The processor period in which one image transitions to another forms no part of theclaimed design.

CLAIM I claim the ornamental design for a display screen or portionthereof with transitional graphical user interface, as shown anddescribed.